Biperiden and trihexyphenidyl are known as anticholinergic antiparkinsonism drugs and are used for the adjunctive treatment of all forms of parkinsonian syndrome. They are administered by injections or tablets. The medicament which is orally administered, for example, as tablets and absorbed in the body are inevitably subjected to decomposition in the digestive organs and primary metabolism in the liver. Accordingly, it is desired to adopt a percutaneous absorption method through the skin surface in consideration of the availability of the administered medicament, long-lasting pharmacological effects and convenience in administration.
With the above-described conventional technique in view, the present inventors have carried out an extensive investigation on the percutaneous absorption of biperiden, trihexyphenidyl or pharmacologically acceptable salt thereof such as biperiden hydrochloride or trihexyphenidyl hydrochloride. As a result, it has been found that a percutaneous absorption preparation which has excellent percutaneous absorption and is stable can be obtained by incorporating such an active ingredient in a skin contact base in an amount ranging from 0.5 to 60% by weight.